The Oscar winner was about to start work on the film with Nicole Holofcener, who also wrote the screenplay, when the two women reportedly fell out, prompting Fox Searchlight bosses to put a hold on the production.

Holofcener then opted to step down as director, explaining Moore's exit was "traumatic" and "terrible", and encouraged Heller to take her place and recast.

Heller agreed to take over and brought in McCarthy to play late celebrity-biographer-turned-forger Lee Israel in her movie.

The project has become one of the year's surprise hits, picking up a handful of top awards nominations, but interviewers keen to get the gossip about the drama which prompted both Moore and Holofcener to walk away won't get anything out of the director and her leading lady.

"All of that happened before I had anything to do with the movie...," the moviemaker tells The Hollywood Reporter. "This particular movie had a different incarnation, which I wasn't a part of, and Melissa McCarthy and I made a pact when we came on board - (we said), 'Let's never talk about whatever happened before, because clearly there is a reason it fell apart. We want to move forward with good feelings'."

"We loved this character; she was a character whose voice, we felt, we didn't get to hear in movies very often."